🚀 go-pugleaf

Arthur Cinader wrote:
> 
> I am teaching myself to program with "How To Program C++" by
> Deitel & Deitel.  A great book.  In chapter eight, there is a
> an example in the text on operator overloading.  When I code
> the example, exactly as it appears in the book, I don't get
> the output that they show...
> 
> Using g++ v2.4 on BSDI I compile with:
> 
> g++ -o fig8.3 fig8.3.C
> 
> here is the source:
> 
> ********begin source
> // FIG8_3.CPP
> // Overloading the stream-insertion and
> // stream-extraction operators.
> #include <iostream.h>
> 
> class PhoneNumber {
>    friend ostream &operator<<(ostream &, const PhoneNumber &);
>   friend istream &operator>>(istream &, PhoneNumber &);
> private:
>    char areaCode[4];  // 3-digit area code and null
>    char exchange[4];  // 3-digit exchange and null
>    char line[5];      // 4-digit line and null
> };
> 
> // Overloaded stream insertion operator (cannot be
> // a member function).
> ostream &operator<<(ostream &output, const PhoneNumber &num)
> {
>    output << "(" << num.areaCode << ") "
>           << num.exchange << "-" << num.line;
> 
>    return output;     // enables cout << a << b << c;
> }
> 
> // overloaded stream extraction operator
> istream &operator>>(istream &input, PhoneNumber &num)
> {
>    input.ignore();                 // skip (
>    input.getline(num.areaCode, 4); // input area code
>    input.ignore(2);                // skip ) and space
>    input.getline(num.exchange, 4); // input exchange
>    input.ignore();                 // skip dash (-)
>    input.getline(num.line, 5);     // input line
> 
>    return input;      // enables cin >> a >> b >> c;
> }
> 
> main()
> {
>    PhoneNumber phone; // create object phone
> 
>    cout << "Enter a phone number in the "
>         << "form (123) 456-7890:" << endl;
> 
>    // cin >> phone invokes operator>> function by
>    // issuing the call operator>>(cin, phone).
>    cin >> phone;
> 
>    // cout << phone invokes operator<< function by
>    // issuing the call operator<<(cout, phone).
>    cout << "The phone number entered was:" << endl
>         << phone << endl;
>    return 0;
> }
> 
> *******end source
> 
> Here is the execution:
> 
> % ./fig8.3
> Enter a phone number in the form (123) 456-7890:
> (800) 555-1212
> The phone number entered was:
> (800) -
> %
> 
> The output should be the full number.
> 
> I tested the value of the PhoneNumber object with
> printExchange() and printLine() functions.  Both print
> funtions printed nothing leading me to conclude that the
> culprit is the function:
> 
> friend istream &operator>>(istream &, PhoneNumber &);
> 
> I am stumped!  Is there a switch I need to throw to make
> operator overloading work with g++?  A search of the man pages
> has turned up nothing.
> 
> Thnaks for any light you can shed!
> 
> Best Regards,
> 
> Arthur
> acinader@panix.com

Try out this for your input function:

// overloaded stream extraction operator
istream &operator>>(istream &input, PhoneNumber &num)
{
   input.ignore();                 // skip (
   input.get(num.areaCode, 4, ')'); // input area code
   input.ignore(2);               // skip ) and space
   input.get(num.exchange, 4, '-'); // input exchange
   input.ignore();                 // skip dash (-)
   input.getline(num.line, 5);     // input line

   return input;      // enables cin >> a >> b >> c;
}

The function getstring seems to read the whole line, so it was 'eaten'
when you read your areaCode.

Oliver Kurth